Anti-fouling spark ignition devices

ABSTRACT

An axially elongated member is provided with an antechamber at one end thereof for receivably engaging the firing end of a spark ignition device. The axially elongated member includes a diverging-converging exit nozzle in its other end and a narrow bore or port extending between and connecting the antechamber with the exit nozzle. The nozzle&#39;&#39;s exit aperture is formed in the end face of the member and thus defines an annular baffle means axially displaced from the point where the narrow bore opens into the exit nozzle. Because of its diverging-converging construction the interior recess of the nozzle is enlarged with respect to the diameter of its exit aperture which latter, in turn, is enlarged with respect to the diameter of the narrow bore or port. The axial member further includes means for preventing a fluid flowing along a wall surface perpendicular to the axis thereof from flowing over the end face of its other end and entering the enlarged interior recess of the exit nozzle.

United States Patent 1 Warner 1 Jan. 16,1973

[54] -ANTI-FOULING SPARK IGNITION DEVICES [73] Assignee: EldapatGeneral, lnc., Morris Plains,

22 Filed: Aug. 7, 1970 21 Appl. No.: 61,933

[52] US. Cl ..l23/l69 R, 123/169 P, 123/169 PA, 313/138 [51] Int. Cl...H01t 13/02 [58] Field ofSearch.....123/169,R,169 CL, 169 CM, 123/169CA, 169 CB, 169 DW,169 EL, 169

EC, 169 C, 169 E, 169 G, 169 P, 169 PA,

169 PB, 169 PH, 169 V; 313/138 Wright ..l23/169 PA PrimaryExaminerLaurence M. Goodridge Att0rney-S. Michael Bender [57] ABSTRACTAn axially elongated member is provided with an antechamber at one endthereof for receivably engaging the firing end of a spark ignitiondevice. The axially elongated member includes a diverging-convergingexit nozzle in its other end and a narrow bore or port extending betweenand connecting the antechamber with the exit nozzle. The nozzles exitaperture is formed in the end face of the member and thus defines anannular baffle means axially displaced from the point where the narrowbore opens into the exit nozzle. Because of its diverging-convergingconstruction the interior recess of thenozzle is enlarged with respectto the diameter of its exit aperture which latter, in turn, is enlargedwith respect to the diameter of the narrow bore or port. The axialmember further includes means for preventing a fluid flowing along awall surface perpendicular to the axis thereof from flowing over theend-face of 'its other end and entering the enlarged interior recess ofthe exit nozzle.

18 Claims, 5 Drawing Figures PATENTEDJAN 16 I975 3. 7 1 0,772

sum 1 or 2 FIG./.

INVENTOR RICHARD C. WARNER 8W M ATTORNEY PATENTEDJAN 16 I975 3.710.772

SHEET 2 BF 2 INVENTOR RICHARD C. WARNER W W ATTORNEY ANTI-FOULING SPARKIGNITION DEVICES The present invention relates generally to sparkignition devices and more particularly to an improved antifouling sparkplug for use in internal combustion engines or the like. The termanti-fouling spark plug as applied to the present invention refers to aspark plug having means associated therewith for preventing oil,v

carbon, and other debris from lodging in or near the electrode gap ofthe plug and thus preventing such foreign matter from interfering withthe proper operation of the plug.

Anti-fouling spark plugs have been proposed heretofore wherein thespaced electrodes forming the sparking gap are recessed in anantechamber formed in an axially protruding extension of the spark plugsshell. The chamber which completely encloses the sparking electrodes atone of its axial extremities, communicates with a narrow apertured boreor port at its other opposed extremity. This port or bore communicates,in turn, with the principle combustion chamber or cylinder of theinternal combustion engine with which the plug is used. By situating theelectrodes at one end of the antechamber and providing a narrowapertured bore at the other opposed end of the antechamber the sparkplugs electrodes are normally shielded or baffled from the oil anddebris swirling about in the engines combustion chamber. However, theatomized fuel/air mixture can easily penetrate the narrow bore openingto the antechamber and may readily be ignited when the spark plug fires.The resulting flames are then expelled through the narrow bore becauseof the rapid pressure increase in the antechamber to ignite the mainmixture in the principle combustion chamber.

Although the prior art anti-fouling spark plugs have generally operatedsatisfactorily with certain types of internal combustion engines, theyhave been found to suffer from the major disadvantage of being extremelycritical with regard to their location. In a great many modern internalcombustion engines, particularly those used in automobiles, trucks, andother vehicles, the

spark plug receiving ports in the engine wall are positioned so that theplugs firing end extends into the combustion chamber below the cylindersintake and exhaust valves. In addition, when the plugs are screwed intotheir corresponding ports, they usually assume a slightly tiltedattitude with respect to a local horizontal direction, that is, with thefiring .end of the plug being slightly raised with reference to itsterminal or rearward end. Such engine arrangements are generallyreferred to as being of the overhead valve type.

It is well known that droplets of lubricating oil occassionly seep orescape through the valve stem seals in such engines, especially when thelatter have been in use for a considerable time and are beginning toshow signs of wear. These droplets of oil tend to flow downwardly alongthe walls of the combustion chamber under the influence of gravity untileventually they reach the exposed electrodes of the plugs, causingfouling and improper firing of same. Even when antifouling plugs areemployed, the oil manages to flow into and through the narrow bore orport of the plugs antechamber and because of the slight upward cant ofthe plug, readily pools or collects around the electrodes thus foulingthe plug nonetheless. Only when the antifouling plug is mounted in anengine where the orientation of the spark plug receiving ports requiresthe firing end of the spark plug to be lower than the plugs rear ward orterminal end will gravity help to keep oil from pooling at theelectrodes and eventually causing improper firing thereof. It is readilyapparent therefore that such prior art anti-fouling plugs are in fact,totally ineffectual in preventing fouling due to oil pollution when usedin engines requiring a static mounting position for the plugs that ismore or less horizontal.

Accordingly, it is the primary object of the present invention toprovide an improved spark plug means having unique features ofconstruction for effectively preventing fouling of the plugs electrodesby foreign matter or debris.

It is another object of the presentinvention to provide an improvedspark plug means that is particularly resistant to the fouling effectsof oil.

It is yet another object of the present invention to provide an improvedanti-fouling spark plug means that can be mounted in a substantiallyhorizontal static operating position in an internal combustion engine,

yet will not be affected by the polluting effects of oil or' otherengine debris. v

To the accomplishment of these and other objects and advantages, theimproved anti-fouling spark plug means of the present inventioncomprises an axially extending outer shell member including an interiorcavity adapted for receiving therewithin a sparking discharge means. Theouter shell member further comprises a terminal portion adapted toextend into the combustion chamber or cylinder of an internal combustionengine and has a diverging-converging recess formed interiorly thereoftodefine an exit nozzle or chamber. The cavity and the chamber areconnected by a narrow axial bore or port having a diameter smaller thanthe mouth or exit aperture of the chamber which aperture, in turn, has adiameter smaller than the major diameter of the chamber itself. A secondgrooved annulus formed exteriorly on the outer shell members terminalportion near the shell members axial extremity completely surrounds theexit aperture of the nozzle.

Additional features and advantages of the present invention will be mademore apparent from a study of the following detailed description of theinvention in connection with the accompanying drawings wherein:

FIG. 1 is a front view of the improved spark plug of the presentinvention; g

FIG. 2 is a sectional view in side. elevation of the spark plug of FIG.1 taken along line 2-2;

FIG. 3 is an enlarged detail view of a fragmentary portion of FIG. 2;

FIG. 4 is a side view partly in section of an alternate preferred formof the present invention, and;

FIG. 5 is a side view partly in section of yet another alternativelypreferred form of the presentinvention.

Turning now to FIGS. 1 and 2, there is shown one preferred form of theimproved spark plug according to the present invention comprising aninsulating core member 10 coaxially received within an outer shellmember 12. The core member 10 which may be of porcelain, ceramic orother such heat resistant non-conductive material, has longitudinallydisposed thereinan elongated central electrode 14. One end of electrode1 14 is integrally connected to a conductive terminal post 16 while itsopposed other end protrudes slightly from the tapered end portion of theinsulating core member as shown at reference numberal 18. The coremember. is clamped in or otherwise fixedly secured to the outer shellmember with a pair of sealing gaskets or the like 20 and 22 beingdisposed therebetween. It will be appreciated that any conventionalmethod of clamping the core member within its outer shell may beemployed, and since this aspect of construction forms no part of thepresent invention, it need not be further discussed herein. I

As viewed in FIG. 2, outer shell member 12 has formed exteriorly thereonnear its left most end, a radially flanged portion 24 having suitablehexagonally faced edges (FIG. l) capable of receiving a spanner wrenchor similar tool. The right-most or extreme axial end of the outer shellmember terminates in a portion of reduced size having suitable threads26 thereon for cooperatively engaging the spark-plug receiving port ofan internal combustion engine. As will be explained in more detailbelow, the extremity of this reduced-size threaded end portion of theouter shell member is necked-down to form a substantially V-shapedgrooved annulus 28 concentrically surrounding the mouth or firing end ofthe spark plug.

The outer shell member carries a pair of opposed ground electrodes 30,32 which extend laterally into a cavity 34 formed within the interior ofthe outer shell member and surrounding the protruding end 18 of thecentral electrode 14. Each ground electrode 30, 32 is radially spacedfrom the common center electrode 14 so as to form a'pair of sparkinggaps inconjunction therewith. As will occur to those skilled in the art,and depending upon individual requirements, a single ground electrode(not shown) extending into cavity 34 in axially spaced relation tocentral electrode 14 may be used to form a single gap instead of the twoformed when the dual electrodes 30, 32 are employed. As shown, cavity 34opens into another cavity 36 interiorly of outer shell/member l2 and thetwo cavities 34 and 36 together define an antechamber therein completelyenveloping the sparking gaps formed among spaced electrodes 14, 30 and32 at one end thereof. An axial connecting port or bore 38 having adiameter of reduced size extends between cavity 36 at the other end ofthe antechamber and a pair of inverted frusto conical chambers 40 and 42forming the mouth or exit nozzle for the spark plug. With thisconstruction, a mixture of atomized fuel and air can easily enter theantechamber (cavities 34 and 36) and be ignited by a spark dischargeacross the electrode gaps defined by electrodes 14, 30, 32. The rapidpressure increase accompanying such ignition within the confines of theantechamber will expel] a jet or tongue of flame through the port 38 andthe exit nozzle of the plug thereby igniting the main mixture inside theprincipal combustion chamber of the engine.

On the other hand, due to the advantageous unique construction of thepresent invention, all forms of particle debris or foreign matter and inparticular, engine lubricating oil, are effectively prevented fromentering the antechamber and polluting the spark plugs electrode gaps aswill now be explained with referenceto FIGS. 1 and 3 wherein likereference numberals represent like parts. It was mentioned previouslythat the mouth or exit nozzle of the spark plug is surrounded by asubstantially V-shaped groove or annulus 28. As

annulus is machined or otherwise formed so that preferably one of itssidesor walls 44 is coplanar with respect to the inner wall surface 46of the engine's principle combustion chamber when the spark plug isscrewed in place. The other side or wall 48 thus formed by groove 28extends away from the wall surface 46, at an acute angle, to form aflared .or funnel shaped protrusion extending slightly into the enginesprinciple combustion chamber as shown, disposed within this flaredextremity of the spark plug is the exit mouth or nozzle previouslyalluded to comprising the two inverted frusto conical chambers 40 and42. Preferably, the exit mount and more particularly, the two frustoconical chambers 40 and 42 are formed by machining a second V-shapedannular groove 50 in the protruding extremity of the outer shell memberafter bore 38 has already been formed therein. In accordance with thepresent invention the outer frusto conical chamber 42 and theinvertedinner frusto conical chamber 40 formed by groove 50 are arrangedsubstantially as shown in FIG. 3 with the diameter of the exit aperture52 formed by the inter-section of chamber 42 with the flat outer endface 54 of 'thc flared extremity of the plug being greater than thediameter of the port or bore. 38 as clearly shown in FIGS. 1 and 3.

cal chambers 40, 42 this diameter may be referred to hereinafter and inthe appended claims as the exit mouth's major diameter.

In operation, it will be appreciated that the overhanging constructionof the flat end face 54 of the plugs axially protruding extremityprovides an annular radially extending shield or baffle that iseffective in preventing substantiallyall impinging particles of carbonor other debris from entering the port or bore 38. Only if suchparticles have a substantially flat trajectory do they stand a chance ofentering the mouth or bore of the plug. And when this occurs, theentering particles are usually expelled during thenext firing of theplug by. the jet of flame issuing through the port 38.

Moreover, due to the V-shaped grooved annulus 28 surrounding theprotruding extremity of the plug, any. oil droplets flowing along theinner wall 46 of the engines combustion chamber asindicated by the arrow56 in FIG. 3 for example, will be entrapped by the groove and caused toflow around the, flared extremity rather than flowing over the end faceof the plug and into the bore 38 as is the case-in prior artanti-fouling plugs. In the event some splashed oil does happen to findits way onto the protruding end face 54 and flows into the mouth definedby chambers 40,42, the oil will merely collect or pool at the bottom ofthe exit mouth formed by groove 50 as represented schematically byreference numeral 58. When the pooling oil accumulates sufficiently torise above the level determined by the lower lip of the exit aperture52, the excess will merely flow over this lip under the influence ofgravity and be discharged from the mouth. Because the majorConcentrically diameter of the exit mouth is axially located relativelynearer to the exit aperture 52 than it is to the bore 38 as clearlyshown in FIG. 3, and further because the exit aperture 52 is greater indiameter than the bore 38, the lip formed by the exitaperture willalways be lower in elevation than the bore; hence, the accumulating poolof oil can not rise sufficiently in the mouth-of the plugto establishbackflow into and through the port 38 and thus into the antechamber ofthe plugs outer shell. It is thus seen that when the spark plug of thepresent invention is disposed in a nominally horizontal position ascalled for in great number of modern internal combustion engines, it isfor all intents and purposes impervious to the deleterious effects ofoil and will not foul even under conditions of severe leaking ofengine-valve oil-seals.

Although the improved spark plug of FIGS. 1-3 is represented at 58received within the anti-fouling spark plug adapter generally designatedby reference numeral 60. As shown, adapter 60 forms an axial extensionfor the spark plug and toward this end includes an internally threadedbore or cylindrical passage 62 for cooperatively engaging theconventional externally threaded inner end'of the spark plug. Theadapter 60 also includes a hexagonally faced flanged portion 64 adaptedto be engaged by the usual spark plug spanner. In all other respects theadapter spark plug configuration of FIG. 4 is identical to the one-pieceplug of FIGS. 1-3 and is used in exactly the same way, that is, theentire assembly is screwed into a corresponding spark plug receivingport in the wall of the combustion chamber or cylinder of an internalcombustion engine as depicted by way of illustration in FIG. 4.

Finally, in FIG. 5, there is shown yet another alternative preferreedembodiment of the present invention comprising an anti-fouling means 66integrally formed within the cylinder or combustion chamber wall 68 ofthe engine as an axial extension of the conventional spark plugreceiving port 70. The wall 68 has a slightly greater width than usualto accommodate the anti-fouling means 66, which latter includes thenarrow apertured bore communicating with the exit mouth or nozzle formedof two inverted frusto-conical chambers as in both previously describedembodiments of the invention. The anti-fouling means of FIG. 5, however,aside from its integral construction within the engine or combustionchamber wall proper differs significantly from both previous embodimentsin that the axial extremity or end face 72 of the unit is flush orcoplanar with respect to the inner wall surface 74 of the combustionchamber or cylinder. This, in turn, requires that an annular groove 76concentrically surrounding the end face 72 be cut or recessed into theinner wall surface 74 so as to provide means for entrapping oil flowingalong the inner wall surface in substantially the same way as groove 28(FIG. 3) accomplishes this function. And although the flush constructionof the end face 72 and the inner wall surface 74 is disclosed herein inconnection with the embodiment of FIG. 5, it will be appreciated thatany of the other preferred forms of the present invention describedabove may be modified in a similar manner to suit those applicationswhere even a slight projection into the combustion chamber or cylinderof the engine cannot be tolerated.

From the foregoing, it should now be apparent that the present inventionprovides a drastically improved spark plug device including means foreffectively preventing fouling of the spark plugs electrodes despite thepresence of oil or other foreign matter in the engines combustionchamber and the unfavorable static horizontal mounting position of thespark plug.

While several preferred embodiments have been disclosed hereinabove byway of illustration,it will be understood that many alterations,modifications, and variations may be made within the spirit and scope ofthe present invention without departing from the principlesthereof asdefined in the appended claims.

I claim:

.1. Apparatus for use with a spark ignition device including aninsulting core body and a center electrode carried by said core body andprotruding therefrom at one end thereof, comprising:

an axially extending member adapted for cooperative engagement with saidspark ignition device; said member including an interior cavity forreceivably enclosing said-protruding center electrode, an exit mouthaxially displaced from said cavity, and a connecting port extendingbetween said cavity and said exit mouth, one end of said connecting portcommunicating with said interior cavity and the other end of saidconnecting port I communicating with said exit mouth;

said exit mouth having an exit aperture axially displaced from saidother end of said connecting port, the diameter of said exit aperturebeing greater than the diameter of said port, said exit mouth forming adiverging-converging interior recess having a major diameter axiallydisposed between said other end of said connecting port and said exitaperture, said major diameter of said divergingconverging recess beinggreater than the diameter of said exit aperture. I

2. The apparatus of claim 1 wherein said axially extending memberincludes a remotely disposed end face defining its axial extremity,said-exit aperture being located in said end face.

3. The apparatus of claim '1 wherein said major diameter. of saidconverging-diverging recess is axially located relatively nearer to saidexit aperture than to said other end of said connecting port.

4. The apparatus of claim 2 wherein said end face is substantially flatand defines an annular radially extending baffle axially displaced fromsaid other end of said connecting port and surrounding said exitaperture.

5. The apparatus of claim 2 wherein said end face of said axiallyextending member is adapted for cooperation with the inner wall surfaceof an internal com- 'bustion engine and includes means for preventing afluid flowing along said inner wall surface from flowing over said endface and entering the interior recess of said exit mouth.

6. The apparatus of claim wherein said last mentioned means includes anannular groove recessed into the exterior surface of said axiallyextending member near said end face, said annular groove being locatedadjacent to said inner wall surface when said member is in cooperativeengagement therewith.

7. The apparatus of claim 6 wherein said end face is flush with respectto said inner wall surface.

8. The apparatus of claim 6 wherein said end face extends beyond saidinner wall surface.

9. The apparatus of claim 1 wherein said insulating core body ispositioned within an outer shell member surrounding said protrudingelectrode, and said interior cavity is adapted to threadedly receivesaid outer shell member in sealing engagement therewithin.

10. The apparatus of claim 1 wherein said insulated core body ispositioned within an outer shell member integrally joined with saidaxially extending member.

1 l. The apparatus of claim 1 wherein'said axially extending membercomprises the wall of an internal combustion engine.

12. The apparatus of claim 5 wherein said axially extending memberincludes an externally threaded porantechamber at one end and an exitnozzle at the other end, narrow passageway means for communicating theinner end of said antechamber with the inner end of said exit nozzle,said exit nozzle having means for preventing fluid such as oil fromentering the narrow passageway means and collecting in said antechamberwhen said outer shell member ismaintained in a substantially horizontalposition, said last mentioned means including an annular lip formed atthe outer extremity of said exit nozzle, saidtannular lip defining anexit aperture of smaller diameter than the inner portion of said nozzle,said narrow passageway mans being of smaller diameter than said aperturewhereby any oil flowing along said wall surfacefrom entering said exitnozzle.

tion adjacent said end face for engaging an internally 16. The apparatusof claim 15 in which said means exteriorily formed with respect to saidexit nozzle comprises an annular roove surrounding said exit nozzlel 17.The appara us of claim 16 in whlch said annular groove defines anoutwardly flared extremity at said other end of said outer shell member,said outwardly flared extremity terminating in a substantially flat endface, said exit nozzle having its exit aperture located in the plane ofsaid flat end face.

18. The apparatus of claim 14 wherein said antechamber is adapted toreceivably engage the firing end of said spark plug device.

1. Apparatus for use with a spark ignition device including an insultingcore body and a center electrode carried by said core body andprotruding thErefrom at one end thereof, comprising: an axiallyextending member adapted for cooperative engagement with said sparkignition device; said member including an interior cavity for receivablyenclosing said protruding center electrode, an exit mouth axiallydisplaced from said cavity, and a connecting port extending between saidcavity and said exit mouth, one end of said connecting portcommunicating with said interior cavity and the other end of saidconnecting port communicating with said exit mouth; said exit mouthhaving an exit aperture axially displaced from said other end of saidconnecting port, the diameter of said exit aperture being greater thanthe diameter of said port, said exit mouth forming adiverging-converging interior recess having a major diameter axiallydisposed between said other end of said connecting port and said exitaperture, said major diameter of said diverging-converging recess beinggreater than the diameter of said exit aperture.
 2. The apparatus ofclaim 1 wherein said axially extending member includes a remotelydisposed end face defining its axial extremity, said exit aperture beinglocated in said end face.
 3. The apparatus of claim 1 wherein said majordiameter of said converging-diverging recess is axially locatedrelatively nearer to said exit aperture than to said other end of saidconnecting port.
 4. The apparatus of claim 2 wherein said end face issubstantially flat and defines an annular radially extending baffleaxially displaced from said other end of said connecting port andsurrounding said exit aperture.
 5. The apparatus of claim 2 wherein saidend face of said axially extending member is adapted for cooperationwith the inner wall surface of an internal combustion engine andincludes means for preventing a fluid flowing along said inner wallsurface from flowing over said end face and entering the interior recessof said exit mouth.
 6. The apparatus of claim 5 wherein said lastmentioned means includes an annular groove recessed into the exteriorsurface of said axially extending member near said end face, saidannular groove being located adjacent to said inner wall surface whensaid member is in cooperative engagement therewith.
 7. The apparatus ofclaim 6 wherein said end face is flush with respect to said inner wallsurface.
 8. The apparatus of claim 6 wherein said end face extendsbeyond said inner wall surface.
 9. The apparatus of claim 1 wherein saidinsulating core body is positioned within an outer shell membersurrounding said protruding electrode, and said interior cavity isadapted to threadedly receive said outer shell member in sealingengagement therewithin.
 10. The apparatus of claim 1 wherein saidinsulated core body is positioned within an outer shell memberintegrally joined with said axially extending member.
 11. The apparatusof claim 1 wherein said axially extending member comprises the wall ofan internal combustion engine.
 12. The apparatus of claim 5 wherein saidaxially extending member includes an externally threaded portionadjacent said end face for engaging an internally threaded spark plugreceiving port communicating with said inner wall surface.
 13. Theapparatus of claim 1 wherein said diverging-converging interior recessforming said exit mouth comprises a pair of inverted frusto-conicalchambers having an imaginary common base the diameter of which conformsto said major diameter, said common base being axially located nearer tosaid exit aperture than to said other end of said connecting port. 14.Anti-fouling means for use with a spark plug device, comprising: anouter shell member having an antechamber at one end and an exit nozzleat the other end, narrow passageway means for communicating the innerend of said antechamber with the inner end of said exit nozzle, saidexit nozzle having means for preventing fluid such as oil from enteringthe narrow passageway means and collecting in said antechamber when saidouter shell Member is maintained in a substantially horizontal position,said last mentioned means including an annular lip formed at the outerextremity of said exit nozzle, said annular lip defining an exitaperture of smaller diameter than the inner portion of said nozzle, saidnarrow passageway mans being of smaller diameter than said aperturewhereby any oil tending to collect within the inner portions of saidnozzle will flow outwardly over said lip before backflowing through saidpassageway into said antechamber.
 15. The apparatus of claim 14 whereinsaid other end of said outer shell member is adapted for cooperationwith the inner wall surface of an engine, and said last mentioned meansfurther comprises means exteriorly formed with respect to said exitnozzle in the vicinity of said wall surface for preventing said fluid asmay be flowing along said wall surface from entering said exit nozzle.16. The apparatus of claim 15 in which said means exteriorily formedwith respect to said exit nozzle comprises an annular groove surroundingsaid exit nozzle.
 17. The apparatus of claim 16 in which said annulargroove defines an outwardly flared extremity at said other end of saidouter shell member, said outwardly flared extremity terminating in asubstantially flat end face, said exit nozzle having its exit aperturelocated in the plane of said flat end face.
 18. The apparatus of claim14 wherein said antechamber is adapted to receivably engage the firingend of said spark plug device.